Tune a ranger random forest model

Usage

tune_ranger(
  cvfold_list,
  metric = "wape",
  y_var,
  id_vars,
  pred_vars,
  tune_grid = NULL
)

cvfold_list: a nested list of cv_sets, each with analysis and assessment
metric: metric to use to select best fit. Options are output of eval_performance.
y_var: string name of column of observed values
id_vars: names of columns used as keys/ids in data.frames
pred_vars: vector string of predictor variables to use in model
tune_grid: grid of parameters to tune over, with each column values for a parameter. If Default (NULL) will create one within the function.

vector of best fitting parameters